1. Field of the Invention
This invention concerns the field of reaction injection molded elastomers.
Reaction injection molded elastomers make excellent molded parts useful, for example, in the automobile industry as exterior parts for vehicles.
2. Description of Related Publications
U.S. Pat. Nos. 4,396,729; 4,444,910 and 4,433,067 concern elastomers prepared using a high molecular weight amine terminated polyether, an aromatic diamine chain extender and an aromatic polyisocyanate which may merely be a polyisocyanate or a quasi-prepolymer prepared from a polyol reacted with a polyisocyanate wherein some isocyanate groups are still left unreacted. Various patents have been applied for and received using the basic combination recited above as well as various mold release agents and other additives.
U.S. Pat. No. 4,585,850 concerns and claims a reaction injection molded elastomer made by reacting in a closed mold amine terminated polyethers of greater than 1500 average molecular weight, having greater than 50% of their active hydrogens in the form of amine hydrogens, a chain extender, flaked glass pretreated with amino silane coupling agent, and an aromatic polyisocyanate. The '850 patent referred to above contains a discussion of other applications and patents in the field and is incorporated herein by reference.
Included in the discussion in the '850 patent are U.S. Pat. Nos. 4,474,900, 4,582,887 and Ser. No. 763,502 filed Aug. 8, 1985 which will issued as U.S. Pat. No. 4,607,090 on Aug. 19, 1986 relate to various types of glass fillers in RIM. The disclosures of these are also incorporated herein by reference.
An article in Plastics Engineering (May 1978) by John Foley of Witco Chemical Corp. discusses the use of surfactants as internal mold release agents.
Quillery's U.S. Pat. No. 3,523,918 describes the use of amine chain extenders for the preparation of integral skin foams. Also, Weber, et al's. U.S. Pat. No. 4,218,543 describes the use of high molecular weight polyols, certain aromatic diamines and isocyanates for the production of RIM parts. This Bayer patent specifically claims as a chain extender 1-methyl-3,5-diethyl-2,4-diaminobenzene (diethyltoluene diamine) and its isomer.
Turner's U.S. Pat. No. 4,246,363 claims a RIM polyurethane composition derived from using at least three different polyols (including amine terminated polyethers) having specific relationships and reactivity and solubility parameters to one another. Also, Vanderhider's U.S. Pat. No. 4,269,945 claims a process for preparing RIM polyurethanes wherein a relatively high molecular weight hydroxyl containing polyol, a chain extender and a polyisocyanate are used. The chain extender may be an aliphatic amine containing material having at least one primary amine group.
The paper "Silane Effects and Machine Processing in Reinforced High Modulus RIM Urethane Composites," by E. G. Schwartz, et al., Journal of Elastomers and Plastics, volume 11 (October 1979), page 280, describes the use of silane treated milled glass fibers in reinforced RIM composites.
The article "Surface Modification for RRIM Urethanes," by Ed Galli, Plastics Compounding, (January/February 1982) discloses silane treated glass fiber reinforcement of RRIM urethanes. The emphasis is on amino silanes.
The publication "Silane Coupling Agents," by Dow-Corning Corporation discusses various silane coupling agents and their applications.
U.S. Pat. No. 4,474,900 discloses and claims the use of epoxy modified filler material in RIM elastomers made from high molecular weight amine terminated polyethers and/or polyols.
An advertisement and specification sheet for the product GLASSCLAD.RTM. 18 (described as a monomeric octadecylsilane derivative in a solution of t-butanol and diacetone alcohol) discloses its use as surface treatment for glass. GLASSCLAD 18 is available from Petrarch Systems of Levittown, PA.
We have found that the impact properties of reinforced reaction injection molded elastomers (RRIM) are improved by the use of octadecyltriethoxysilane believed to be the monomeric octadecylsilane derivative in GLASSCLAD 18 discussed above.